The present invention relates to mooring floating vessels such as pleasure boats, and particularly relates to mooring boats alongside piers or moorage floats.
When a boat is moored alongside a pier or float by use of lines, fenders are traditionally placed between a side of the boat and the face of the pier or float to prevent damage to the side of the boat. A fender can prevent serious structural damage, but where currents and storm waves cause significant, prolonged movement of a boat relative to the pier or float, fenders rubbing on the boat's hull can eventually cause considerable damage to the paint or other surface finish. Fenders, moreover, are subject to being pulled or rolled out of their proper locations where there is a great deal of movement of a boat relative to the pier or other moorage structure, as when tides, storm waves, or currents urge the boat toward the pier or float or cause large vertical movements of the boat relative to the pier face.
In order to prevent excessive motion of a boat alongside a pier it has been necessary in the past to adjust conventional mooring lines in response to tidal rise and fall of the water with respect to the pier. While such adjustment of mooring lines to accommodate tides is not a problem for a boat moored to a float free to rise and fall on the tide, it is sometimes difficult to limit movement of a boat alongside a float to the extent desired without undesirably straining mooring lines when the boat moves relative to the float in response to storm waves or wakes of passing vessels.
One attempt to solve these old problems is disclosed in Booker et al. U.S. Pat. No. 4,250,827, which teaches use of opposing helical compression springs to control relative linear movements of telescopically sliding parts of an arm, to hold a boat, connected to the outer end of the arm, at a desired distance from a pier. When the device is not in use, an elbow spring raises the arm to a tilted, upwardly-extending position. The elbow spring also accommodates vertical motion of the boat relative to the pier. Although the combination of the opposing compression springs and elbow spring provides the necessary elastic resistance to the motion of the boat, it has several significant disadvantages. The sliding telescopic action of the compression springs and arm can be extremely noisy, creating a constant annoyance, particularly after the moving parts have been exposed to the weather for some time. Also, the structure requires three springs and a complex telescopic arm, which makes it expensive. If the sliding telescopic action of the compression springs is eliminated, the elbow spring alone is too short to provide a sufficient range of resilient resistance to movement of the boat toward and away from the dock, which overstresses the portion of the boat to which the arm is attached. Another disadvantage of this device is that it will perform differently depending upon the freeboard height of the particular boat moored to it, because variations in such height significantly change the angular attitude of the arm relative to the elbow spring, whose height cannot easily be adjusted. Finally, the elbow spring raises the arm to a tiled, rather than vertical, position when not in use. Such tiled position can present an obstacle to the docking of a boat of sufficient freeboard height.
Yordi U.S. Pat. No. 2,996,033 discloses a device which includes a cable located within an elbow spring connecting an arm to a base. This cable limits elastic extension of the spring which, similarly to the problem discussed above, provides an insufficient range of resilient resistance to movement of the boat toward or away from the dock, thereby overstressing the point of attachment of the arm to the boat. Also, no easy adjustability of the spring height is provided to avoid significant changes in arm attitude for boats having different freeboard heights.
Kulick U.S. Pat. No. 2,938,492 teaches use of a helical coil spring extending upward from a base mounted on a boat. The top end of the spring is linked together with an arm of adjustable length which has an opposite end detachably fastened to the structure of a pier. The boat can move horizontally a limited distance as the arm causes the upper end of the generally vertically-extending spring to bend resiliently. However the spring, not being prestressed by the weight of the boat and allowing large horizontal deflections at its top without significant stress, would offer insufficient resistance to boat movement toward or away from the dock to be able to contain such movement within an acceptably small range. The Kulick device, moreover, requires a special fitting mounted on the boat to hold the spring, and thus presents the spring as an obstruction on deck on the boat. While the spring can be removed from the fitting, its removal and replacement detract from convenience of use of the device. Also, the spring provides no elbow function for automatically raising the arm when not in use, creating a further inconvenience.
Olsen U.S. Pat. No. 2,912,953 discloses use of a horizontally-oriented helical spring with a ring mounted at its distal end to fasten a small boat to an anchor post rather than a pier or float. Such a device, however, offers little range of resilient resistance to movement, is likely to be very noisy as the ring slides up and down along the anchor post, and is clearly not well adapted for use with anything but very small boats.
Steinhauer U.S. Pat. No. 1,094,610 discloses a device which rigidly holds a small boat with respect to longitudinal motion parallel to the face of a pier, while including a push-pull dual compression spring mechanism similar to that used in the Booker device to control lateral movement of the boat. The device thus has drawbacks similar to those of the Booker et al. device mentioned above.
Gorman U.S. Pat. No. 2,552,424 discloses an arrangement of helical springs intended to control movement of a small boat by application of spring tension to move the boat in a required direction to maintain its position. The arrangement, however, requires a boat to be placed within a slip where the devices can be attached to the boat from each side, and from the front.
Smith U.S. Pat. No. 2,569,783 discloses a device including an arm of a fixed length interconnecting a ball joint located on a boat with an attachment point located on a pier. While vertical motion and a limited amount of fore-and-aft movement of the boat are permitted by the arrangement, the fixed length of the connecting arm severely limits the freedom of the boat to move laterally, causing unnecessarily large forces to be concentrated on the boat at the point of attachment of the arm to the boat.
Fulton U.S. Pat. No. 3,120,831 discloses a long resiliently flexible mooring whip, to be bent and attached to a boat moored by conventional mooring lines, to pull the boat away from a pier or float by the elastic forces of the whip. The device is very long and somewhat unsightly in construction, however, and rather than establishing a neutral mooring position for a boat, the device always tends to keep tension in at least some of the mooring lines.
Faber, Jr. U.S. Pat. No. 3,157,150 discloses a device including a connecting arm pivotally spring-mounted on a base and including a suspended spring carried at the distal end of the connecting arm to connect the arm to a small boat. The multi-spring arrangement would be expensive, and the suspended distal spring would provide little resistance to boat movement toward or away from the dock within an acceptably small range.
What is needed, then, is a mooring device of simple, inexpensive construction, capable of very quiet operation and useful for boats of large and small sizes alike, either in combination with or independent of conventional mooring lines, to control movement of a boat with respect to a dock with sufficient resilient resistance without imposing undue stress on either the boat or the dock and thereby reduce dependence on conventional fenders. Preferably the device should be easily adjustable to operate similarly for boats of different freeboard heights.